This study will investigate the relationship-of waking blood pressure to sleep-induced apnea/hypopnea and high upper airway resistance associated with snoring. We will experimentally eliminate sleep disordered breathing (SDB) and snoring with nasal continuous positive airway pressure (CPAP) treatment in mild and moderate hypertensives and determine the effect on 48 hour ambulatory blood pressure measurements and nocturnal catecholamine release. We hypothesize that the elimination of nocturnal respiratory with 2 weeks of nasal CPAP will result in a reduction in blood pressure in mild/moderate hypertensive subjects with SDB and snoring but will not affect arterial pressure in those subjects without SDB and snoring. We predict that increased nocturnal catecholamine release will be correlated with daytime blood pressure control in subjects who lower their blood pressure during CPAP therapy. The main objective of the study is the application of nasal CPAP, an intervention that can rapidly reverse SDB and snoring, and the measurement of blood pressures and urinary catecholamine release before, during and after the intervention.